The present invention relates to plasma devices. More particularly, the present invention relates to an improved plasma processing device.
Plasma processing devices may be used in manufacturing. Plasma processing devices may use power systems to generate and sustain a plasma.
To facilitate discussion, FIG. 1 is a schematic view of a prior plasma processing device 10, comprising a plasma process unit 12, a pump manifold 14 supporting the plasma process unit 12, a lower transfer chamber 16 supporting the pump manifold 14, and a power source 18 connected to the lower transfer chamber 16. The plasma process unit 12, pump manifold 14, and lower transfer chamber 16 collectively form a plasma process module. The plasma process unit 12, comprises an upper electrode 20 spaced apart from a lower electrode 22. A lead 24 extends from the lower electrode 22, through the pump manifold 14 and the lower transfer chamber 16 to provide an electrical connection between the lower electrode 22 and the power source 18. An example of a power source 18 is a One Box(trademark) radio frequency (rf) power source, which comprises a first generator 28, a second generator 30, and a match box 32 electrically connected to the first generator 28 and the second generator 30. In this example, the first generator 28 provides a 2 MHz output and the second generator 30 provides a 27 MHz output. The match box 32 may provide electrical diagnostics and impedance matching. An output connector 34 extends from the match box 32. The lead 24 is electrically connected to the output connector 34, which may be a 5 inch diameter piece of silver coated copper plug and where the lead may be connected to the output connector 34 by a screw or bolt. Nut and bolt sets 36 may provide a mechanical connection to connect the power source 18 to the lower transfer chamber 16. A bottom cover 38 covers the bottom of the lower transfer chamber 16. An interlock switch 40 is placed near the cover 38 and is electrically connected to the first generator 28 and the second generator 30, so that when the cover is removed from the lower transfer chamber 16 the interlock switch 40 causes the first generator 28 and the second generator 30 to be powered down to reduce electrical shock hazards.
In the testing of the power source 18 in the prior art, to facilitate discussion, FIG. 2 is a schematic view of a power source 18 of a plasma processing device being tested and FIG. 3 is a flow chart of the testing procedure of the power source 18.
In the testing of the power source 18, a power source problem may be suspected (step 304). The first and second generators 28, 30 may be turned off and powered down (step 308). The power source 18 may be disconnected from the plasma process module (step 312), which might take 15 to 30 minutes. To do this, the bottom cover 38 may be removed from the lower transfer chamber 16 to provide access to nut and bolt sets 36. The removal of the bottom cover 38 may trigger the interlock switch 40, which may shut down the generators 28, 30 if they are not already turned off. The nut and bolt sets 36 may be removed. Typically a power source 18 may be connected by 6 to 7 nut and bolt sets 36. In addition, the lead 24 may be disconnected from the output connector 34. The power source 18 may be moved away from the plasma process module (step 316) to create enough space to connect the load simulator 44, which might take 5-45 minutes. A load simulator 44 connected to a 50 ohm terminator 46 may be connected to the output connector 34 of the power source 18 (step 320). The generators 28, 30 may be turned on and powered up (step 324) which may take 10 minutes, to determine if there are any problems with the power source 18 (step 328). Diagnostic instruments within the first and second generators 28, 30 or within the match box 32 may be able to determine if the power source 18 is working properly, when connected to the load simulator 44.
If it is determined that the power source 18 is working correctly, then to reconnect the power source, the first and second generators 28, 30 may be powered off (step 332). The power source 18 may then be disconnected from the load simulator 44 and the power terminator 46 (step 336). The power source 18 may then be moved to the plasma process module (step 340). The lead 24 may be connected to the output connector 34. The power source 18 may then be connected to the lower transfer chamber 16 of the plasma process module (step 344). The 6 to 7 nut and bolt sets 36 may be used to complete the connection. The bottom cover 38 may be placed on the lower transfer chamber 16 to set the interlock switch 40 so that it is not triggered. The first and second generators 28, 30 may the be powered on (step 348).
The connecting and disconnecting of the power source 18 and the powering up and powering down of the generators may be time consuming and hazardous and may require a high level of expertise to be done correctly. In addition, the connecting and disconnecting of the output connector 34 and the lead 24 may cause the connection between the output connector 34 and the lead 24 to be less reliable. The many steps involved increase the chance of mistakes with high voltage and current devices.
In view of the foregoing, it is desirable to provide a simple method and apparatus for testing a power source of a plasma process device.
The invention relates, in one embodiment, to a plasma processing apparatus, comprising: a plasma process module; an electrode within the plasma process module; a switch electrically connected to the electrode; a load simulator electrically connected to the switch; a power source electrically connected to the switch, wherein the switch is electrically connected between the power source and the load simulator.
The invention relates, in a second embodiment, to a method for testing a generator in a plasma processing device while the generator is running, comprising the steps of: setting the generator to provide a near minimum (which is low or zero) power output, while the generator remains on; through a switch electrically connected to the generator, connecting a load simulator to the generator; increasing the output of the generator; and determining if the generator is providing sufficient power.